Fluoride is an environmental and industrial pollutant that affects various organs in humans and animals. The cecal tonsil is an important component of the mucosal immune system and performs important and unique immune functions. In the present study, we investigated the effects of dietary high fluorine on the quantities of IgA+ B cells in the cecal tonsil by immunohistochemistry, and the immunoglobulin A (IgA), immunoglobulin G (IgG) and immunoglobulin M (IgM) contents in the cecal tonsil by ELISA. A total of 280 one-day-old avian broilers were divided into four groups and fed on a corn-soybean basal diet as control diet (fluorine 22.6 mg/kg) or the same diet supplemented with 400, 800 and 1,200 mg/kg fluorine (high fluorine groups I, II and III) in the form of sodium fluoride, respectively, throughout a 42-day experimental period. The results showed that the quantities of IgA+ B cells were lower (p < 0.05 or p < 0.01) and the IgA, IgG, and IgM contents were decreased (p < 0.05 or p < 0.01) in high fluorine groups II and III in comparison with those of control group. It was concluded that dietary fluorine, in the 800–1,200 mg/kg range, could reduce the numbers of the IgA+ B cells and immunoglobulin contents in the cecal tonsil, implying the local mucosal immune function was ultimately impacted in broilers.

Long-term excessive fluoride intake is known to be toxic and can lead to fluorosis and bone pathologies. However, the cellular mechanisms underlying sodium fluoride-induced cytotoxicity in the cecal tonsil lymphocytes are not well understood. The aims of this study were to investigate the effects of high dietary fluorine on apoptosis and the expression of the Bcl-2, Bax, and caspase-3 in the cecal tonsil lymphocytes of broilers. The broilers were fed on high-fluorine diets containing 0, 400, 800, and 1,200 mg/kg fluorine. As measured by flow cytometry, the percentage of apoptotic lymphocytes was significantly increased in the high-fluorine groups II and III when compared with those in the control group. Meanwhile, immunohistochemical tests showed that the Bcl-2 protein expression decreased, and the Bax and caspase-3 protein expression increased in the high-fluorine groups II and III. In conclusion, dietary fluorine in the range of 800-1,200 mg/kg increased lymphocyte apoptosis in the cecal tonsil of broilers, suggesting that the lymphocyte apoptosis in the cecal tonsil was mediated by direct effects of fluoride on the expression of Bcl-2, Bax, and caspase-3.

The objective of this study was to determine the effects of dietary vanadium on small intestinal morphology of broilers by the methods of light microscopy (LM) and transmission electron microscopy (TEM). A total of 420 one-day-old avian broilers were divided into six groups (seven replicates in each group and ten broilers in each replicate) and fed on a control diet or the same diet supplemented with 5, 15, 30, 45 and 60 mg/kg vanadium in the form of ammonium metavanadate for 42 days. In comparison with those in the control group, the intestinal villus heights were decreased (P < 0.05 or P < 0.01) in the 30, 45 and 60 mg/kg groups, and crypt depths and villus height/crypt depth ratio were decreased in the 45 and 60 mg/kg groups. Ultrastructurally, the microvilli were apparently sparse and short, and the numbers of lysosomes were increased in abovementioned three intestines in the 45 and 60 mg/kg groups at 42 days of age. In conclusion, dietary vanadium in excess of 30 mg/kg could alter the villus height, crypt depth, villus height/crypt depth ratio and ultrastructure, which might impact the development of small intestines in broilers.

As part of our study on the effects of high F on lymphoid organs and tissues of broilers, the oxidative damage to their cecal tonsil induced by dietary high F was observed while feeding them a control diet containing 22.6 mg F/kg and three high F diets containing 400, 800, and 1200 mg F/kg for high F groups I, II, and III throughout a 42-day experimental period. The results showed that malondialdehyde (MDA) content was significantly higher (p<0.01) in high F groups ll and III than in the control group. In contrast, the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px), glutathione (GSH) contents, and ability to inhibit hydroxyl radical were significantly decreased (p<0.01) in high F groups II and III in comparison with those in the control group. In conclusion, dietary F, in the range of 800-1200 mg/kg, could induce oxidative damage and impair the antioxidation and immune function of the cecal tonsil in broilers.

The cecal tonsil of broiler is known as a secondary lymphoid tissue, which is involved in antigen-specific humoral immune responses. The purpose of this study was to investigate the effects of dietary vanadium on the tissue distribution and quantity of immunoglobulin A-positive (IgA+) cell in the cecal tonsil by immunohistochemistry. Simultaneously, the changes in interleukin-6 (IL-6), interleukin-10 (IL-10), interferon gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α) contents in the cecal tonsil were also quantified by enzyme-linked immunosorbent assay (ELISA). A total of 420 one-day-old avian broilers were divided into six groups and fed on a corn–soybean basal diet (control diet) or the same diet supplemented respectively with 5, 15, 30, 45, and 60 mg/kg of vanadium in the form of ammonium metavanadate for 42 days. The results showed that the population of the IgA+ cells in the cecal tonsil were significantly lower (p < 0.05 or p < 0.01) in the 45 and 60 mg/kg groups than that in the control group. Meanwhile, IL-10, IFN-γ and TNF-α contents in the cecal tonsil were significantly decreased (p < 0.05 or p < 0.01) in the 30, 45 and 60 mg/kg groups in comparison with those of the control group. However, IL-6 content in the cecal tonsil was only decreased (p < 0.05 or p < 0.01) in 60 mg/kg at 14 and 28 days of age. In conclusion, dietary vanadium in excess of 30 mg/kg reduced the numbers of the IgA+ cells and changed the contents of the abovementioned cytokines in the cecal tonsil, which may finally impact the function of local mucosal humoral immunity in broilers.

The purpose of this 42-day study was to examine the effect of dietary vanadium on intestinal microorganism diversity in the duodenum, ileum, cecum, and rectum segments of broilers by the plate count and polymerase chain reaction-denaturing gradient gel electrophoresis (DGGE). A total of 420 1-day-old avian broilers were divided into six groups and fed on a control diet or the same diet supplemented with vanadium at the doses of 5, 15, 30, 45, and 60 mg/kg in the form of ammonium metavanadate. In comparison with control group, the dietary vanadium at the doses of 45 and 60 mg/kg could decrease the counts of Bifidobacterium spp. in the intestinal tract at 21 and 42 days of age. With increasing level in dietary vanadium, the counts of Escherichia coli were significantly increased in the ileum, cecum, and rectum and were decreased in the duodenum at 21 and 42 days of age. However, the counts of Lactobacilli were decreased in the cecum and rectum and increased in the ileum of 45 and 60 mg/kg groups. The colonization of these three bacteria could be affected by dietary vanadium. DGGE analysis showed that the number of bands in duodenum, ileum, cecum, and rectum were obviously decreased in the 30, 45, and 60 mg/kg groups at 21 and 42 days of age. In conclusion, the dietary vanadium in excess of 30 mg/kg could alter the amount and diversity of intestinal bacteria in broilers, implying that the structure and initial balance in the intestinal microbiota were disrupted.

The purpose of this study was to investigate the renal and hepatic oxidative damage and toxicity caused by dietary high vanadium in broilers. A total of 420 one-day-old avian broilers were divided into six groups and fed on a corn-soybean basal diet as control diet (vanadium 0.073 mg/kg), and five high vanadium diets (vanadium 5 mg/kg, high vanadium group I; 15 mg/kg, high vanadium group II; 30 mg/kg, high vanadium group III; 45 mg/kg, high vanadium group IV; and 60 mg/kg, high vanadium group V) throughout the experimental period of 42 days. The results showed that the renal and hepatic superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities, ability to inhibit hydroxy radical, and malondialdehyde (MDA), glutathione, and vanadium contents were not significantly changed in high vanadium group I and II when compared with those of the control groups. However, the SOD and GSH-Px activities, ability to inhibit hydroxy radical, and GSH content were significantly decreased, and the MDA and vanadium contents were markedly increased in high vanadium groups III, IV, and V. At the same time, the lesions were also observed in the kidney and liver of high vanadium groups III, IV, and V. The renal tubular epithelial cells showed granular degeneration and vacuolar degeneration, and hepatocytes showed granular degeneration, vacuolar degeneration, and fatty degeneration. It was concluded that dietary vanadium in the range of 30-60 mg/kg could cause oxidative damage and vanadium accumulation, which induced renal and hepatic toxicity and lesions. The renal and hepatic function was finally impaired in boilers.

As part of our study on the effects of high dietary fluorine (F) on organs and tissues, changes in the fatty acid composition of breast muscle of broilers fed diets containing 400, 800, and 1200 mg F/kg were observed throughout a period of 42 days. The results showed that the contents of stearic acid (C18:0), eicosanoic acid (C20:0), behenic acid (C22:0), myristoleic acid (C14:1), oleic acid (C18:1), alpha-linolenic acid (C18:3n-3), linoleic acid (C18:2n-6), gamma-linolenic acid (C18:3n-6), and arachidonic acid (C20:4n-6) were significantly higher (p<0.01), mainly in the high F groups II and III than in the control group. In contrast, especially in these two groups, the contents of myristic acid (C14:0), palmitic acid (C16:0), lignoceric acid (C24:0), hexacosanoic acid (C26:0), palmitoleic acid (C16:1), erucic acid (C22:1), eicosapentaenoic acid (C20:5n-3, EPA), and docosahexaenoic acid (C22:6n-3, DHA) were significantly lower (p<0.01) than in the control group. In conclusion, feeding broilers high F diets alters fatty acid composition in broiler breast muscle, including saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs), and polyunsaturated fatty acids (PUFAs). The likelihood of an adverse impact of these changes on the quality and flavor of chicken breast and other muscle qualities must also be kept in view.

As part of our recent studies on the effects of high fluorine (F) on the cecal tonsil of newly hatched chickens, the same broilers with 400, 800, and 1200 mg F/kg in their diet were used to investigate the changes in the cecal tonsil content of the cytokine proteins interleukin-4 (IL-4), interleukin-6 (IL-6), tumour necrosis factor alpha (TNF-alpha), and interferon gamma (IFN-gamma) by enzyme-linked immunosorbent assay (ELISA). The results showed that the content of these cytokines in the cecal tonsil was significantly lower (p<0.05 or p<0.01) in the high F groups II and IIII than in the control group. Lower cytokine levels in the cecal tonsil can impact the local immune function of intestines by affecting pathways that decrease the lymphocyte numbers and/or lymphocyte activation.

As part of our study on the effect of high fluorine (F) on cecal tonsil, changes in the percentages of subsets and IL-2 contents in the cecal tonsil T-cells were investigated in broilers fed high F diets containing 400,800, and 1200 mg F/kg. The percentages of CD3+, CD3+CD4+, and CD3+CD8+ T-cells in the cecal tonsil were significantly decreased (p<0.05 or p<0.01) in high F groups II and III; however, the CD4+/CD8+ ratio was not significantly changed. Meanwhile, interleukin-2 (IL-2) contents in the cecal tonsil were also lower (p<0.05 or p<0.01) in high F groups II and III than those in the control group. In conclusion, dietary F in the range of 800 similar to 1200 mg/kg reduced the percentages of cecal tonsil T-cell subsets and IL-2 contents, implying that the local mucosal immune function can be adversely impacted by high F in broilers.

The purpose of this study was to examine oxidative stress induced by dietary vanadium in the mucosa of different parts of intestine including duodenum, jejunum, ileum, and cecal tonsil. A total of 420 1-day-old avian broilers were divided into six groups and fed on a corn–soybean basal diet as control diet or the same basal diet supplemented with 5, 15, 30, 45, and 60 mg/kg vanadium as ammonium metavanadate. During the experimental period of 42 days, oxidative stress parameters were determined for both control and experimental groups. The results showed that malondialdehyde content was significantly higher (p < 0.05 or p < 0.01) in 30, 45, and 60 mg/kg groups than in control group. In contrast, the activities of superoxide dismutase, catalase, and glutathione peroxidase, and ability to inhibit hydroxyl radical, and glutathione hormone content were significantly decreased (p < 0.05 or p < 0.01) mainly in 45 and 60 mg/kg groups in comparison with those of control group. However, the abovementioned oxidative stress parameters were not significantly changed (p > 0.05) in 5 and 15 mg/kg groups. It was concluded that dietary vanadium in excess of 30 mg/kg could cause obvious oxidative stress in the intestinal mucosa, which could impact the antioxidant function of intestinal tract in broilers.

The purpose of this 42-day study was to examine the effect of dietary vanadium on the ileac T cells and contents of cytokines including interleukin-2 (IL-2), interleukin-6 (IL-6), and interferon-gamma (IFN-γ) in broilers by flow cytometry and enzyme-linked immunosorbent assay. A total of 420 one-day-old avian broilers were divided into six groups (seven replicates in each group and ten broilers in each replicate) and fed on control diet or the same diet supplemented with 5, 15, 30, 45, and 60 mg/kg vanadium in the form of ammonium metavanadate. The results showed that the percentages of CD3(+), CD3(+)CD4(+), and CD3(+)CD8(+) T cells in both ileac lamina propria lymphocytes (LPLs) and intraepithelial lymphocytes (IELs) were significantly lower (P < 0.05 or P < 0.01) in the 45- and 60-mg/kg groups than in the control group from 14 to 42 days of age. The CD4(+)/CD8(+) ratio was increased in ileac LPLs in the 60-mg/kg group at 28 days of age, and in ileac IELs in the 60-mg/kg group at 28 days of age and in the 45-mg/kg group at 42 days of age. Meanwhile, the ileac IL-2, IL-6 contents were decreased (P < 0.05 or P < 0.01) in the 60-mg/kg group from 14 to 42 days of age and in the 45-mg/kg group from 28 to 42 days of age in comparison with those of the control group. It was concluded that dietary vanadium in excess of 30 mg/kg reduced the ileac T cell population and percentages of T cell subsets, and IL-2, IL-6, and IFN-γ contents, implying that the immune function of local intestinal mucosa in broilers could be affected by the dietary vanadium.

The purpose of this 42-day study was to investigate the effects of dietary excess vanadium on intestinal immune function by histopathological observation of cecal tonsil and changes of the cecal tonsil T cell subsets by method of flow cytometry. Four hundred twenty 1-day-old avian broilers were divided into six groups and fed on a corn–soybean basal diet as control diet or the same diet amended to contain 5, 15, 30, 45, and 60 mg/kg vanadium supplied as ammonium metavanadate. In comparison with those of control group, lymphocytes in the lymphatic nodule of cecal tonsil were apparently decreased in 45 and 60 mg/kg groups. The percentage of CD 3 + T cells was decreased (p < 0.05) in 45 mg/kg group at 28 and 42 days of age and significantly decreased (p < 0.01) in 60 mg/kg group at 28 and 42 days of age. The percentages of CD 3 + CD 4 + and CD 3 + CD 8 + T cells were markedly decreased (p < 0.05 or p < 0.01) in 60 mg/kg group from 14 to 28 days of age and were decreased (p < 0.05) in 45 mg/kg group at 28 and 42 days of age. However, changes of the CD 4 + /CD 8 + ratio were not significant. Meanwhile, the cecal tonsil interleukin-2 (IL-2) contents were decreased (p < 0.05 or p < 0.01) in 45 and 60 mg/kg groups from 14 to 42 days of age. It was concluded that dietary vanadium in excess of 30 mg/kg reduced the percentages of cecal tonsil T cells subsets and IL-2 contents, and caused cecal tonsil lesions, which impaired cecal tonsil function and impacted the local mucosal immune function of the intestines in broilers.